HDU3047+并查集

带权的并查集

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 1 /*

 2 带权值的并查集

 3 ps:对于两个不在同一个集合里面的两个元素，把父节点接在一起即可

 4 */

 5 #include<stdio.h>

 6 #include<string.h>

 7 #include<stdlib.h>

 8 #include<algorithm>

 9 #include<iostream>

10 #include<queue>

11 #include<map>

12 #include<math.h>

13 using namespace std;

14 typedef long long ll;

15 //typedef __int64 int64;

16 const int maxn = 50015;

17 const int inf = 0x7fffffff;

18 const double pi=acos(-1.0);

19 const double eps = 1e-8;

20 

21 int dis[ maxn ],fa[ maxn ];

22 

23 void init( int n ){

24     for( int i=0;i<=n;i++ ){

25         dis[ i ] = 0;

26         fa[ i ] = i;

27     }

28     return ;

29 }

30 int find( int x ){

31     if( fa[x]==x ) return x;

32     int tmp = find( fa[x] );

33     dis[ x ] = dis[ x ]+dis[ fa[x] ];

34     dis[ x ] = dis[ x ]%300;

35     fa[ x ] = tmp;

36     return fa[ x ];

37 }

38 bool unionab( int a,int b,int c ){

39     int x = find(a);

40     int y = find(b);

41     //printf("fa[%d]=%d,fa[%d]=%d,dis[%d]=%d,dis[%d]=%d\n",a,x,b,y,a,dis[a],b,dis[b]);

42     if( x==y ){

43         if( ((dis[b]-dis[a]+300)%300)!=c ){//b在a的后面，保证是dis[b]-dis[a]

44             //printf("test:%d %d\n",a,b);

45             return false;

46         }

47     }

48     else{

49         dis[ y ] = dis[ a ]+c-dis[ b ]+300;

50         dis[y] %= 300;

51         fa[ y ] = x;

52     }

53     return true;

54 }

55 int main(){

56     int n,m;

57     while( scanf("%d%d",&n,&m)==2 ){

58         int a,b,c;

59         init( n );

60         int res = 0;

61         while( m-- ){

62             scanf("%d%d%d",&a,&b,&c);

63             bool f = unionab( a,b,c );

64             if( f==false ) res++;

65         }

66         printf("%d\n",res);

67     }

68     return 0;

69 }